Xerox Corporation

Fred J Long

Robert S Schreiber

John R Gilbert

Siddhartha Chatterjee

Shang-Hua Teng

An optimizing compilation process generates executable code which defines the computation and communication actions that are to be taken by each individual processor of a computer having a distributed memory, parallel processor architecture to run a program written in a data-parallel language. To this end, local memory layouts of the one-dimensional and multidimensional arrays that are used in the program are derived from one-level and two-level data mappings consisting of alignment and distribution, so that array elements are laid out in canonical order and local memory space is conserved. Executable code then is generated to produce at program run time, a set of tables for each individual processor for each computation requiring access to a regular section of an array, so that the entries of these tables specify the spacing between successive elements of said regular section resident in the local memory of said processor, and so that all the elements of said regular section can be located in a single pass through local memory using said tables. Further executable code is generated to produce at program run time, another set of tables for each individual processor for each communication action requiring a given processor to transfer array data to another processor, so that the entries of these tables specify the identity of a destination processor to which the array data must be transferred and the location in said destination processor's local memory at which the array data must be stored, and so that all of said array data can be located in a single pass through local memory using these communication tables. And, executable node code is generated for each individual processor that uses the foregoing tables at program run time to perform the necessary computation and communication actions on each individual processor of the parallel computer.

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San Diego, CA, United States of America

Fred J Long